Particulate matter transfer system

ABSTRACT

A METHOD OF FACILITATING FLOW FROM A VESSEL THROUGH A FLOW CONTROL MEANS WHICH INVOLVES SENSING THE PRESSURE BUILD-UP AGAINST THE FLOW CONTROL MEANS AND AUTOMATICALLY RELIEVING THE PRESSURE TO EFFECT RESUMPTION OF FLOW.

1971 e. s. woons; JR 3556,59

PARTICULATE MATTER TRANSFER SYSTEM Filed April 7, 1969 INVENTOR. G.S. WOODS, JR,

v a tomvers United States Patent "ice US. Cl. 302-66 7 Claims ABSTRACT OF THE DISCLOSURE A method of facilitating flow from a vessel through a flow control means which involves sensing the pressure build-up against the fiow control means and automatically relieving the pressure to effect resumption of flow.

This invention relates to transfer of particulate matter.

In one of its more specific aspects, this invention relates to means for facilitating the flow of particulate matter.

In many processes, low density particulate material is fed from a supply source to a subsequent point where the particulate matter is desired at constant rates and in uniform quantities.

Feeding the particulate matter to its ultimate destination at constant rates from the supply source is often difiicult due to gas accumulation, or binding, with the establishment of pockets which obstruct the flow of the particles from the system. Gases can also be intentionally introduced into the system in order to upset bridging which takes place within the supply source, and this gas tends to form obstructing pockets.

The supply source is frequently constructed with a lower conical hopper and discharges through a valve, rotary feeder, or other flow regulator. The particles tend to bridge within the hopper and the gases tend to accumulate under the bridge and against the flow regulator, this gas pocket tending to further obstruct flow through the flow regulator and from the supply source. Furthermore, pockets of gas can be established at other points within the supply source and these contribute to erratic outlet flow rates. Relief of such pressurized gas pockets from the system by venting frequently creates problems related to the combustive nature of the gases, atmospheric pollution and upset subsequent operations.

The method of this invention provides a simple method for relieving the pressure which builds up against a regulator of flow from a supply source. According to the process of the invention, there is provided a method for obtaining uniform flow of particulate matter from a supply source through a fiow control means positioned on the outlet thereof which comprises sensing the pressure within the supply source on the upstream side of the flow control means, establishing flow in a conduit in by-pass relationship to the flow control means in response thereto from the upstream side of the flow control means to relieve gaseous obstruction to flow, establishing flow of the particulate matter from the supply source through the flow control means.

Accordingly, it is an object of this invention to provide a method of maintaining continuous uniform flow of particulate matter from a supply source.

It is another object of this invention to provide a method which automatically maintains uniform flow of particulate solids from a feed system to a point of subsequent processing.

The method of this invention will be more easily understood if explained in conjunction with carbon black processing, as indicated in the attached drawing which shows, schematically, one embodiment of the method 3,556,506 Patented Jan. 19, 1971 of the invention, but without meaning to limit the invention thereto.

In carbon black processing, black is frequently fed from a surge tank or a conveyor, either of which act as a supply source, through a rotary feeder into a pelleter into which a pelleting agent can be introduced to facilitate the formation of pellets. For purposes of this example, the black will be considered as being fed from a tank in which gas tends to build up against the rotary feeder positioned at the outlet of the tank. This build up and the arching of the black in the lower section of the tank act to prevent the flow of black to the pelleter at the desired uniform constant rate.

Referring now to the drawing, there is shown collecting cyclone 1 which receives carbon black from inlet conduit 4 and which discharges gases through conduit 5 and carbon black through its outlet 6 through valve 7 into surge tank 2.

Surge tank 2 has a lower conical-shaped hopper section 8 which discharges through rotary feeder 9 into conduit 17 which feeds into pelleter 3.

Pelleter 3 is driven by motor 10 through shaft 11. Pelleter 3 operates generally at atmospheric pressure and is open to atmosphere and discharges the carbon .black in pelleted form through conduit 12.

In the system described, both bridging and gas accumulation occur in hopper section 8 in the area proximate the entrance to rotary feeder 9. Accordingly, there is formed above rotary feeder 9 an area devoid of carbon black, at elevated pressure, such that with the rotation of rotary feeder 9, no carbon black is transferred into conduit 17 and hence into pelleter 3.

The method of this invention contemplates the installation of conduit 14 in open communication with the upstream side of rotary feeder 9 and conduit 15 in open communication with the downstream or pelleter side of rotary feeder 9, or in open communication with any point of lower pressure, these two conduits being interconnected through valve 16. A suitable size for this conduit has been found to be about four inches, this being sufliciently large to prevent vapor lock. Valve 16 is a pneumatically operated wafer-like valve.

Interconnected to hopper section 8 is also pressure controller 13 which is adapted to sense pressure build-up within hopper section 8. Pressure controller 13 is interrelated with valve 16 and adapted to open and close this valve. Pressure controller 13, upon sensing a pressure build-up within hopper section 8, causes valve 16 to open and gases to vent from hopper section 8 into conduit 17 and from the system to the pelleter or to the zone of lower pressure. Flow is facilitated if the pelleter operates under a slight vacuum which can be induced by means not shown. Any particulate carbon black carried with the gases so vented into the pelleter will tend to mix with the carbon black being pelleted in the pelleter.

After relief of the restricting pressure through valve 16, as sensed by pressure controller 13, valve 16 is closed and flow is gravitationally resumed through rotary feeder 9.

While the range of pressure to which this invention is applicable is unlimited, it has been found that such pressures must be considered even though quite low. For example, in the system described above, pressures as low as 1 inch to 2 inches water column differential have been found to adversely affect flow and are preferably relieved in the manner described.

In order to minimize plugging of the by-pass loop formed around valve 9 by conduits 14 and 15, gas inlets can be located in these conduits proximate that point at which they intercept that vertical conduit in which valve 16 is positioned. One inlet can be located in each of the 3 elbows of lines 14 and 15 to discharge vertically towards valve 16 and one inlet can be located in each of the elbows of lines 14 and 15 to discharge horizontally to- Wards hopper section 8 and conduit 17, respectively.

Certain modifications can be made to the above system, these including shielding the pressure tap opening into the surge tank from the pressure controller in order to prevent obstruction with particulate carbon black, and the like. Similarly, it is possible to integrate the operation of the pressure controller with an inlet gas introductory system introducing inert gas into the surge tank to upset the bridging formed therein, the gas automatically being introduced on a time cycle to destroy the bridging and permit restoration of flow from the surge tank. Pressure build-up within the surge tank in this system with gas is, of course, prevented by the opera tion of the pressure controller.

These and similar modifications are, however, within the scope of the invention.

What is claimed is:

1. A method of maintaining uniform flow of particulate matter from a supply source and through a flow control means proximate the outlet of said supply source, which comprises sensing the .pressure within said supply source proximate said flow control means, establishing gaseous flow in by-pass relationship to said flow control means responsive thereto to relieve said pressure and, establihing particulate flow through said flow control means.

2. The method defined in claim 1 in which said gaseous flow is established to a point of lower pressure than the pressure within said supply source.

3. The method defined in claim 1 in which said pressure is maintained at about 1 to about 2 inches of water.

4. The method defined in claim 1 in which at least a portion of the gases flowing in by-pass relationship to said flow control means are introduced to facilitate flow of particulate matter from the supply source.

5. The method of claim 1 in which said particulate matter comprises carbon black.

6. The method of claim 5 in which said gases introduced to establish said gaseous flow are introduced with said carbon black.

7. The method of claim 5 in which said gases introduced to establish said gaseous flow are introduced to upset bridging within said supply.

References Cited UNITED STATES PATENTS 2,726,137 12/1955 Davis Jr. 30266 3,233,945 2/1966 Kurtz 30249 3,380,780 4/1968 Allen et a1. 30253 ANDRES H. NIELSEN, Primary Examiner US. Cl. X.R. 30235, 42, 52 

